Ch 15

The electromagnetic spectrum consists of

• all of the colors of light you can see with your eyes.

• all of the different types of electromagnetic waves.

• a band of colors formed when white light passes through a prism.

• the distance between the crest of one wave and the crest of the next wave.

A range of colors formed when white light passes through a prism is called a

• lens.

• photograph.

• spectrum.

• ray.

A light-year is

• 365 days.

• the distance light travels in a year.

• the distance from Earth to Proxima Centauri.

• the amount of light the sun produces in a year.

Parallax is used to determine a star’s

• distance from Earth.

• temperature.

• composition.

• brightness.

Characteristics used to classify stars include

• distance, size, and color.

• size, distance, and brightness.

• color, brightness, and distance.

• size, brightness, and temperature.

What color are the coolest stars?

• blue-white

• yellow

• red

• orange

A star is born when

• a nebula expands.

• helium and oxygen combine.

• nuclear fusion starts

• protostar begins to cool.

The lifetime of a star depends on its

• temperature

• absolute brightness

• mass

• apparent brightness

A supernova is the explosion of a dying

• medium-mass star.

• high-mass star.

• protostar.

• low-mass star.

Which of the following is a major difference between elliptical galaxies and spiral galaxies?

• Elliptical galaxies have almost no gas or dust between the stars.

• Elliptical galaxies vary more in shape than spiral galaxies.

• Spiral galaxies have almost no gas or dust between the stars.

• piral galaxies contain only old stars.